The Vobis molecular distillation or short path distillation systems with evaporator heat transfer surface area to 100m2 that we design, construct and provide to clients are also called short path evaporator systems and are similar to our wiped film evaporation systems except that they have an internal condenser which is inside of the evaporator and whose condensing surfaces are very close to the film distributed on the heat transfer surface. That the internal condensor is physically so close to the heat transfer surface area of the SPD minimizes pressure drop by reducing the intermolecular interactions of the vapor molecules and allows operation at extremely high vacuums, as low as 0.001 mBar, for use with very heat sensitive natural products.  The high vacuum level lowers the effective boiling point for very gentle evaporation of volatile components.

Similar to a wiped film evaporator, molecular distillation (also known as short path evaporation or SPD) operates with a plug flow throughput of the feed material through the evaporator and a very short residence time.  The high vacuum possible, which lowers the boiling point, and the high surface renewal through wiping the film across the inner wall of the short path evaporator system makes certain that a heat sensitive feed material is treated very gently and minimizes the thermal stress.

Our molecular distillation or short path evaporator systems are constructed in a variety of process wetted materials including stainless steels, titanium, or duplex steels according to application requirements and are complete with feed and harvest vessels, vacuum system, all piping, valves, pumps, and PLC control systems.

The feed material is spread in a thin film on the inside of the heated evaporator body.  Just inside of this and very close to the heated wall which is covered with feed material is the condenser.  The residence time of the feed material at temperature is only seconds before being discharged from the short path evaporator, thus protecting the heat sensitive products of the separation.

Short path distillation or molecular stills are implemented for a wide variety of processes to separate and protect very heat sensitive products.  These include products from the following industries:  flavors and fragrances, polymer, food, chemical, petrochemical, oils and fats, nutraceutical, natural materials such as terpenes and pharmaceutical actives and include applications such as:

  • Free Fatty Acid removal from vegetable oils
  • Solvent separation from silicones
  • Distillation of pharmaceutical actives
  • Flavor and fragrance purifications and separations
  • Fractionation of waxes
  • Fractionation of terpenes
  • Concentration of sweeteners, sugars and fruit products
  • Used oil rerefining
  • Separation of advanced organic intermediates

For laboratory through pilot scale molecular distillation systems, please visit our Vobis pilot molecular distillation website.